You're still talking about interface design and not an error in the actual code. You're talking about how the user is interacting with the software, and/or how a website developer writes up his crappy site. The software itself isn't broken. But the interaction between user and client and server is getting under your skin and you're insisting it is a bug... when it simply is not a bug.

"Every time a try to click this link, my browser crashes!" <--- that sounds like a bug.

"I'm able to create a webpage that exploits a user interaction to create weird behavior" <---- not a bug! if a problem exists it is within the realm of User Interface Design and not software design or anything within the code itself. The design choices may cause a need to rework the code, but that doesn't make a bug magically appear in the code.